The present invention has to do with improvements in that form of soft-sided waterbed frame structure that is the subject matter of U.S. Pat. No. 5,203,040, issued Apr. 20, 1993 and entitled, "Soft-Sided Flotation Mattress Frame." The disclosure of U.S. Pat. No. 5,203,040 is incorporated herein by reference.
The waterbed frame structure which is the subject matter of the above-identified U.S. Patent includes a horizontal, rectilinear, platform established of plywood or equivalent material and that defines a flat horizontal upwardly disposed mattress supporting top surface, a downwardly disposed bottom surface, oppositely disposed longitudinally extending, parallel, side edges or side edge portions; and, oppositely disposed laterally extending, parallel, end edges or end edge portions.
The subject prior art frame structure next includes pairs of like elongate side and end wall sections each of which is coextensive with and overlies a related side or end edge portion of the platform. Each wall section comprises a core of soft resilient foam plastic with a thin flexible exterior jacket about its exterior. Each wall section has a flat, downwardly disposed, longitudinally extending bottom surface with substantially straight parallel inner and outer side edges and end edges. The bottom surfaces of the wall sections overlie and oppose related side and end portions of the platform.
The subject prior art frame structure next includes elongate anchor plates to releasably pivotally secure the lower inner edge portion of each wall section to its related side edge portion of the platform. The anchor plates are elongate, flat, horizontal plate-like parts having longitudinally extending outer portions with longitudinally extending inner and outer edges, substantially transversely or laterally extending end edges, downwardly disposed bottom surfaces and flat, smooth upwardly disposed top surfaces. The anchor plates are coextensive with and are in supported engagement atop their related side and end portions of the platform. The plates are suitably fixed to the platform by means of cement, tacks, staples, or the like, as desired or as circumstances might require.
The anchor plates next include elongate longitudinally extending inner edge portions that extend inwardly from the inner edge portions of their outer portions and that are formed with or carry parts of coupling means to engage related coupling parts that are secured to and carried by the wall sections at or adjacent to the inner edges of the bottom surfaces thereof, to couple the wall sections to the anchor plates for upper and inwardly pivotal movement thereof relative to the platform.
The outer edges of the anchor plates have downwardly extending flanges with inwardly projecting lips at their lower edges. The flanges overlie their related outer edges of the platform to dress those edges of the platform. The lips on the flanges engage the bottom surface of the platform and prevent upwardly displacement of the outer edge portions of the plates.
The anchor plates can be made of any suitable material and fabricated in any suitable manner. In practice, the anchor plates have been provided in the form of aluminum and plastic extrusions. The opposite ends of the wall sections and of the anchor plates are angularly related to the longitudinal axes of the wall sections and plates so that each end surface of each wall section and each end edge of each anchor plate establishes flat opposing engagement with its related end surface and end edge of its next or adjacent wall section and anchor plate. That is, the ends of the wall sections and anchor plates are formed so that they establish miter joints at the four corners of the frame structure.
Pivotally connecting the wall sections to the plates at or near the inner edges of the bottom surfaces thereof enables the wall sections to be pivoted inwardly and upwardly. Such pivoting of the wall sections enables the edge portions of bedding items such as linen sheets and sometimes blankets, that normally overlie the tops of the frame structure and depend about the exterior thereof, to be tucked inwardly between the wall sections and the plates when the bed, of which the frame is a part, is "made up." While the foregoing tucking in of bedding appears to be a function that this prior art bed frame structure might effectively perform, it has been found that bedding that has been tucked in, as noted, will not remain tucked in during normal anticipated use of the bed of which the frame is a part. Because the top surfaces of the anchor plates are smooth and the bottom surfaces of the wall sections are necessarily taut, flat and smooth, bedding tucked between them is so insecurely held that it often appears to be expressed outwardly from between the bottoms of the side walls and the plates when the bed structure is sat upon, brushed against or otherwise worked upon or against in such a way as to cause or induce any relative movement of the several related parts.
In addition to the above, the adjacent end edges of related anchor plates establish sharp, right angle, corners at the four corners of the frame structure that are highly subject to causing injury or damage to persons and/or objects that establish contact therewith, during ordinary activity about and/or use of the bed structure of which the frame structure is a part. In practice, if the opposing end edges of adjacent anchor plates do not mate precisely or are caused to part or separate, as when engaged by a person's body, or the like, the related anchor plates define two closely related acute angled corners (45.degree.) that are highly capable of cutting into or slicing that which is brought into contact with them.